2. Sell crypto for vouchers from wallet A and then sell vouchers again for crypto in wallet B (This should make it hard to link my wallet A to wallet b right?)
No, not really and this depends mainly on the platform you are going to use to buy/sell the voucher. Even if you use two different platforms they may cooperate and exchange information to track your transactions and link your wallets.
Better use a reputable mixer first (if you choose to use the mixer mocacinno suggested then make sure to use the .onion website) then exchange the mixed coins for a privacy coin like montero on a decentralized exchange. You can then send the privacy coins to the CEX and exchange them to whatever coins you want.